The use of microfluidic systems for the acquisition of chemical and biological information is becoming increasingly popular due to a number of considerations. For example, complicated biochemical reactions, when conducted in microfluidic volumes, may be carried out using very small volumes of liquid. As the volume of a particular liquid needed for such testing regimes is small, often on the order of nanoliters, the amounts of reagents and analytes used can be greatly reduced. Reduction in the amounts of reagents and analytes can greatly reduce the costs associated with microfluidic testing compared to conventional testing systems.
In addition, the response time of reactions is often much faster in microfluidic systems, leading to a decrease in the overall time required for a particular test regime. Also, when volatile or hazardous materials are used or generated during testing, performing reactions in microfluidic volumes can increase the safety of a testing regime and can also reduce the quantities of hazardous materials that require specialized disposal after testing is completed.
While microfluidic testing is increasing in popularity, the technology associated with microfluidic testing remains problematic in a number of areas. In particular, it has been found that as liquids are centripetally manipulated through various microchannels and chambers formed on or in microfluidic test coupons, gas bubbles can be formed or entrained in the liquids and can interfere with the testing to be performed on the liquids. This interference can take a variety of forms. For example, when liquid is delivered to an optical test chamber to be optically analyzed, the presence of gas bubbles within the liquid can adversely affect the accuracy of the optical test. In addition, when it is desired to chemically react a liquid with a reactant applied to a surface of a testing chamber, the presence of gas bubbles can reduce the interaction between the liquid and the reactant.
Accordingly, while it is desired to use microfluidic test systems in a wide range of applications, the limitations presented by the presence of gas bubbles in microfluidic manipulation of fluids remain problematic.